fertplan: Compute Components Of NPK Fertilization Plans

# Nitrogen ----------------------------------------------------------------
# Perdite per lisciviazione

# > c1 ----------------------------------------------------------------------
# Metodo in base alle precipitazioni

# Loss of Nitrogen leached by precipitation
#
# Estimates Nitrogen leached by using cumulative precipitation in the period
# October 1st - January 31st as described on pages 24 and 25 of the "Disciplinare".
# This is one of two mutually exclusive methods (c1 and c2) to compute Nitrogen leaching,
# the other being c1 "Metodo in base alla facilità di drenaggio"
# The leaching affects only the available Nitrogen part (not total Nitrogen)
#
# @param available_n      available Nitrogen for the crop, usually returned by \code{\link{b1_available_n}}
# @param rainfall_oct_jan cumulative precipitation in mm in the 4 months-period October - January
#
# @return Nitrogen leaching from soil in the year the precipitation figure is collected, in kg/ha
# @export
#
# @examples
# # Returns 3.3777 i.e. all available Nitrogen was leached
# C_N_precip_leach(3.3777, 350)
C_N_precip_leach <- function(available_n, rainfall_oct_jan) `: numeric` ({

  is_numeric(available_n)
  is_same_length(c(length(available_n), length(rainfall_oct_jan)))
  is_numeric(rainfall_oct_jan)

  is_neg_rainfall <- rainfall_oct_jan < 0
  if (any(is_neg_rainfall)) {
    warning("Unrealistic negative rainfall, assuming 0 mm rainfall")
    rainfall_oct_jan[is_neg_rainfall] <- 0
  }

  n_leached_pc <- leached_n_coeff(rainfall_oct_jan)

  available_n * n_leached_pc
})



# > c2 ----------------------------------------------------------------------
# Metodo in base alla facilità di drenaggio

# Loss of Nitrogen leached yearly by soil drainage rate and texture
#
# Rate of Nitrogren in kg per hactare per year, as in table 3, page 25 of the 'Disciplinare'.
# This is one of two mutually exclusive methods (c1 and c2) to compute Nitrogen leaching,
# the other being c1 "Metodo in base alle precipitazioni"
#
# @param drainage_rate  Rate of drainage in soil (either "fast", "normal", "slow", "no drainage")
# @param soil_texture   Soil texture (either "Sandy", "Loam", or "Clayey")
#
# @return Nitrogen leaching from soil in kg/ha/y
# @export
# @importFrom ensurer ensure
# @examples
# # Returns 30 50
# C_N_drain_leach(c("Rapido", "Lento"), c("Argilloso", "Sabbioso"))
C_N_drain_leach <- function(drainage_rate, soil_texture) `: numeric` ({

  ensurer::ensure(drainage_rate, +is_character, +is_drainage_rate)
  ensurer::ensure(soil_texture, +is_character, +is_soil_texture)
  is_same_length(c(length(drainage_rate), length(soil_texture)))

  match_dt <- lookup_var_by_drainage_texture(
    tables_l[["tab_03_dt"]],
    drainage_rate,
    soil_texture)

  match_dt$n_leached_kg_ha_y
})



# Phosphorus (P) --------------------------------------------------------------
# Immobilizzazione (C)

# Loss of Phosphorus due to immobilization from Limestone content
#
# Supply of Phosphorus (P2O5) in kg per hactare to counteract immobilization due to limestone
#
# @param Ca_pc          Limestone soil content in \% of Cation-exchange capacity
# @param soil_texture   Soil texture (either "Sandy", "Loam", or "Clayey")
#
# @return Phosphorus (P2O5) to be supplied (positive sign) to soil in kg/ha. This is a
# correction factor that takes into account the unavailable P quantity due to limestone content
# @export
# @importFrom ensurer ensure
# @examples
# # Returns 3.246
# C_P_immob_by_Ca(92.3, "Argilloso")
C_P_immob_by_Ca <- function(Ca_pc, soil_texture) `: numeric` ({
  ensurer::ensure(Ca_pc, +is_numeric, +is_vector_pc)
  ensurer::ensure(soil_texture, +is_character, +is_soil_texture)
  is_same_length(c(length(Ca_pc), length(soil_texture)))

  row_idx <- pmatch(
    x             = soil_texture,
    table         = tables_l$C_P_a_coeff_dt[["soil_texture"]],
    duplicates.ok = TRUE)

  a_coeff <- tables_l$C_P_a_coeff_dt[["a_coeff"]][row_idx]
  p_immobilization(a_coeff, Ca_pc)
})